Clamp



Aug. 16,1927. Y 39,56l

. J. M. HARGRAVE CLAMP Filed A112. 9. 1926 mnnfoz damn.

Patented Aug. 16, 1927.

UNITED STATES JOHN M. HARGRAVE, 0F" cm'ci'NNArI, OHIO.

CLAMP.

Application filed August 9, 1926.- Sam No. 129,302.

This invention relates to a type of clamps known as joiners employing alongitudir nal bar having afiXed clamping jaw at one end of the bar anda second jaw slidable upon the bar, and carrying a screw parallel to thebar to cooperate with the stationarybar. The invention: is particularlydirected to the mechanism for bindin'gly holding the jaw in its adjustedpositionon the bar; Thebinding mechanism comprises serrated facedblockscarried by the movable jaw relatively offset and at opposite sides oredges ofthe bar, to grip the edges of the bar with a slight writing ofthe. jaw. The block -isrecessed respectively within holders or insertsmounted with the j'aws;

Theretore an object ofthis invention is to 7 provide; in a work:clamping jaw adjustable on: a longitudinal bar, a pair of toothed blocksrockingly mounted and diagonally located'within opposite sides of thebar engaging bore of the adjustable jaw, the blocks adapted to movetoward the-bar when: the jaw. is; canrtecli due to its outer end beingtorceduagai'nst the work and-the' teeth inclined after the manner of:saw teethin the:

direction in which the jawte'nds' to move ber ins-engagement; withthebar so that the aw is normally sustained in any position on thebarbut so balanced as to be-easilv mov able: when desired.

Another object isvto provide amounting forzthe 'grippingf elements inthe aw bore;

thusflbeing in the nature of blocks secured 1 at each side of the:bore,eachblockgrooved to houseit'hose gripping elements in the same: sideofthe bore namel y a-spl 'ing and a toothed member, and the blocksremovable from the: bore of the jaw wi'thou'tremoval of the" jawfromtheabar, "this-construction beings ofYimporttmcein theLa'ssembly ofthe:

various small elements which would other wise be extremely difficult-toplace in: the jawbore.

Another object is to provide a curved base to the grooves which: containthe toothed membersgso that theseim-embersare allowed to rock thereonand adjust themselves, as the jaw is canted,- for permitting all theteeth of the members to engage the bar with equal effect.

Further objects and certain advantages will be more tully set'forth inthe accompanying drawings; forming a part of this specification, inwhich:

Figure 1 is a sideview of a clamp.

FigureQ, is atop view of the clamp illustrating the relation of themounting blocks to the bar. I

Figure 3 is an enlarged sectional view taken: on line 3-3 of F igure 2,detailing the arrangement and construction of the variousgrlppin-gelements in the clamp jaw.

Figure 4' isa perspective view of a: mounting block removed from thejaw.

Figure 5' is a perspective view of a toothed element removedfrom themounting block. 1 7

Referring to the drawings the clamp comprises a longitudinal rectangularbar 1 having a fixed jaw 2 secured at one end and an adjustable jaw 3slidable longitudinally of th'eba-r inrelation to the fixed jaw; Thefixed jaw 2 is riveted to the bar land has it faced portion 4- on theside toward the adjustable jaw and 'aga'ins't which the work is Theaxljustablejaw 3- carries a screw 5- :threaded through: a projecting end6 of the jaw 3, the screw being" arallel-with the longitudinalr bar. A-wing shaped handle 7 is provided at one end of the screw and a hat headSis pivoted to the other end of the: screw as a work engaging member. Thefiat-head 8: is secured to the screwend by a balland socket-joint sothat the headmay adjust itself to anyirregularities in the work when thework is clamped between said head and the lower jaw.

The longitudinal bar I is madein any lengthand lias a rivet 9 initsoute'rend for preventing the removal of the adjustable clampgjaw.-

The rectangular bore 10 of] the jaw through w'hich the bar" extends ismade ofgrea'ter" width than the bar and mounting blocks'l l ar-e securedwithin this bore at each sidejthereo fl These blocks 1'1 carry the V barengaging elements,- engaging the oppo-1 'siie'edges of the rectangularbar. ,7

Pinsl2- pass through the jaw and mounting blocks and serve to maintainthe blocks in the j aw'bore-whileat the same time they the blocks arepermitted to rock.

are easily driven out and the blocks removed for replacing any worn outparts in blocks.

Each mounting block has two crosswise grooves as at 13, let, eachserving to house respectively springs 15 and a toothed block 16. The twomounting blocks although formed identical are put in the bore inopposite directions so that the toothed blocks 16 are diagonally relatedand the springs are positioned in the same way (see Figure The bore ofthe jaw is of sufficient width that when the mounting blocks areinserted and the bar aligned in the bore there is a slight clearance ateach side of the bar between the bar edge and mounting blocks.

A toothed block 16, described in detail, is rectangular and has one sidetoothed as at 17 after the fashion of saw teeth. Shoulders 18 are formedat each end of the toothed surface and these shoulders are overhung byprojections 19 on the outer end edges of the grooves 14 for looselymaintaining the toothed members in the mounting blocks.

The springs used, are formed of fiat metal turned upon itself and asplaced in the groove they act outwardly from the base of the groovecontaining them against the bar edge. The mounting blocks are of thesame thickness as the bar and the same is true of the various elements,so that the entire bar edge thickness is engaged.

Bringing the screw down upon the work cants the adjustable jaw slightlyand as a result the toothed members may be said to swing in a circle.This action causes the toothed members to be forced against the bar edgewith the result that they dig in slightly and thereby positively gripthe bar. The gripping action of the toothed members is aided by theoutward curvature of the toothed block groove base 20. Due to thisbulging curvature being engaged by the flat base of the toothed blocksand to the fact that the blocks are loose in the groove Theyautomatically adjust themselves to the movement of the jaw and all theteeth engage the bar with equal effect. The teeth are inclined-in thedirection in which they tend to move on the bar under load so that theybite into the bar.

It is readily apparent that this positive jaw grip produced by thepivotal movement of the toothed blocks in their grooves is importantsince the tendency of the aw is not only 'to cant under load but toslide down the bar. lVhen the jawis not in clamping service, the springstend to align the jaw bore in is a spring opposite each'toothed memberthe jaw is balanced and the toothed members are held against the baredge sufficiently to hold the jaw in set position. However. the easymovement of the jaw, when not in service, is not interfered with sincerelation to the bar, and since there.

the spring tension is the factor governing the movement of the jaw andthey are made to resist only the movement of the jaw re sulting from itsown weight or other light forces. Movement of the jaw is further easedby canting the bar in an opposite direction to the cant created bypressure in the work, this disengaging the toothed members from the baredge.

The mounting blocks aid in assembly since it is not necessary to removethe-jaw from the bar to replace the various members. The members areplaced in the mounting blocks and the unit is then slid into the bore atthe side of the bar and the pin set in place. These adjustable jawfeatures are for use on any style bar and where it is inconvenient orimpossible to remove the jaws from the bar due to the shape or positionof the bar, the feature of assembly is of especial importance,

In the smaller size clamps it is only necessary to have the grippingelements at one side of the bar, so that only one insert is used, thatis, a mounting block carrying a toothed block and spring. Also it is tobe noted that the invention relates to the features for positivelyengaging the jaw on the bar so that it is of no importance whether thejaw moves in relation to a fixed jaw or another adjustable jaw. 7

Having described my invention, I claim:

1. In a clamp, a longitudinal bar, an adjustable work engaging jawhaving an aperture therein through which said bar extends, mountingblocks secured in said aperture at opposite edges of said bar, toothedelements and springs mounted in recesses formed by grooves in saidblocks and the side walls of the jaw, the toothed elements diagonallylocated so as to gri the bar when the jaw is canted due to pressureagainst the work andv the springs located opposite each toothed memberso as to normally maintain the teeth. against the bar when the jaw is inset position and not engaging the work.

2. In a clamp, a longitudinal bar, an adjustable work engaging jawhaving an aperture therein through which said bar loosely extends,toothed members and springs, mounting blocks carrying said toothedmembers and springs. in respective grooves, each block with itsvariouselemen'tsbeing identical in, structurev but secured within theaperture at each edge. of the bar in reverse manner so that the toothedmembers are diagonally related, and a spring opposite each toothedvmember for normally" maintaining the teeth against the bar edge.

3. In combinationwitha longitudinal bar and an adjustable jaw a'perturedto receive secured within the aperture at one edge of.

the bar a toothed member loosely seated in said mounting block andhaving its teeth disposed against the .bar edge, a spring mounted withinthe mounting block and normally maintaining the toothed member inengagement with the bar, and said teeth so positioned as to bepositively enga ed against the bar when the jaw is canted ue to pressureat its outer or work engaging end.

4. In a clamp, a longitudinal .bar, an adjustable jaw apertured toreceive said bar and slidable thereon, mounting blocks secured withinthe aperture at opposite edges of the bar, toothed members looselyseated in slots in said mounting block at each edge of said bar, thebase of said slots being out wardly curved to allow the toothed membersto pivot thereon whereby all the teeth of r the members positivelyengage the bar edge when the jaw is canted due to pressure against thework.

within each mounting block and diagonally related, whereby when thej awis canted due to work engaging pressures on its outer end the frictionelements are drawn against and grip the respective bar edges.

In witness whereof, I hereunto subscribe my name.

JOHN M. HARGRAVE.

